ASMR stands for Autonomous Sensory Meridian Response it is described as a pleasurable tingling sensation that can be felt most commonly in the back of the scalp and down the spine but not limited to these area’s.
I try to describe ASMR experience to people using something common like visiting a hairdresser, do you find the experience of someone focusing on you, the gentle touching of your hair, the sound of the scissors moving around you relaxing?
That would be a relaxing experience, watching ASMR video is like recreating that type of experience.
I believe most people can experience ASMR, to experience ASMR you need to find you trigger, common triggers will often be related to one person focusing on you or another person and watching this person focus or give them attention will trigger it.